WITHDRAWN FROM THE ACTION OF GRAVITY. 315 
no tendency to become effaced, it will not be propagated to the subjacent parts, 
and consequently will not give rise toa wave. Hence the portion of the vein 
under consideration will be more dilated from the first than it would have been 
in the absence of vibratory movements; but it will have the same length and 
descend with the same velocity as in this latter case. / 
After the descending vibration will come an ascending one, and this latter 
diminishing the velocity of the passage at the contracted section, there will re 
sult, as has been already remarked, in the portion of the vein which passes 
under its influence, a diminution of volume, so that this portion will tend to be- 
come narrower; but the configurative forces tending to make of this same por- 
tion an incipient constriction, the attenuation due to the vibration will be effected 
without encountering an opposite tendency, and consequently without giving 
rise to the formation of a wave. ‘Thus we see that, as in the case of the dila- 
tation which precedes it, the constriction formed by the double action of the 
contigurative forces and of the vibration will be less decided, but will have the 
same length and\descend with the same velocity as if the vein were abandoned 
to the sole action of the configurative forces. 
In fine, the same thing will take place in regard to all the other dilatations 
and constrictions: in virtue of the equality between the time occupied by each 
of these portions of the vein in passing at the contracted section and the dura- 
tion of each vibration, all the dilatations will coincide with the descending 
vibrations, and all the constrictions with the ascending vibrations ; all will con- 
sequently preserve their length and their velocity of translation, but all will 
quit the contracted section more distinctly defined, or, to use other words, in a 
more advanced phase of transformation, than if vibratory movements had not 
been produced. 
§ 6. But the action of these movements will not be limited to this: in effect, 
the velocities of the ascending and descending vibrations—velocities which, a3 
we have shown, change direction in the dilatations and constrictions to produce 
a greater transverse development of the former and a greater attenuation of the 
latter—cannot be annihilated, in each of these portions, at the moment when its 
passage at the contracted section is finished ; these velocities thus changed into 
transverse velocities will continue therefore, as acquired velocities, to form an 
addition tv those which result from the configurative forces. 
§ 7. In order that the transmitted vibrations shall exert with full intensity 
on the incipient divisions of the vein the action described in the two preceding 
paragraphs, it is necessary that at the orifice they should have, as we have sup- 
posed, a vertical direction. It would be ditticult, doubtless, to show a priori that 
in being propagated to the orifice the vibrations really take that direction; but 
Savart, who has been so much occupied with the communication of vibratory 
movements, admits the fact implicitly : he supposes, in effect, that on the one 
hand these vibrations only reinforce those which arise, according to him, from 
the efflux itself and which would necessarily be vertical, and on the other he 
does not say that, to obtain the maximum of action, it is necessary to give to 
the sonorous instrument any particular position. For the rest, if we find therein 
some diticulty, it would suffice to remark that whatever be the real direction 
in which the liquid molecules, in traversing the orifice, execute the vibrations 
transmitted to them, we may always, save in the wholly exceptional case in 
which that direction is exactly horizontal, decompose each vibration into two 
others, of which the horizontal one will exert no influence on the transforma- 
tion of the divisions of the vein, while the other and vertical one will exert its 
whole action. 
We have supposed, moreover, that the moment when each descending vibra- 
tion commences is also that when the lower extremity of each dilatation passes 
at the contracted section; but if, at the first instant when the vibrations make 
themselves felt, this coincidence does not take place, there will be a coutlict 
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